1. Technical Field
The present disclosure relates to a surgical apparatus for laparoscopic and endoscopic procedures. In particular, the disclosure relates to a surgical apparatus having a drive mechanism for remotely positioning, orienting and operating an end effector.
2. Background of Related Art
Typically in a laparoscopic, an endoscopic, or other minimally invasive surgical procedure, a small incision or puncture is made in a patient's body. A cannula is then inserted into a body cavity through the incision, which provides a passageway for inserting various surgical devices such as scissors, dissectors, retractors, or similar instruments. To facilitate operability through the cannula, instruments adapted for laparoscopic surgery typically include a relatively narrow shaft supporting an end effector at its distal end and a handle at its proximal end. Arranging the shaft of such an instrument through the cannula allows a surgeon to manipulate the handle from outside the body to cause the end effector to carry out a surgical procedure at a remote internal surgical site. This type of laparoscopic procedure has proven beneficial over traditional open surgery due to reduced trauma, improved healing and other attendant advantages.
A steerable laparoscopic or endoscopic instrument may provide a surgeon with a range of operability suitable for a particular surgical procedure. For example, the instrument may be configured such that the end effector may be aligned with a longitudinal axis of the instrument to facilitate insertion through a cannula, and thereafter, the end effector may be caused to articulate or move off-axis as necessary to appropriately position the end effector to engage tissue. When the end effector of a steerable, articulating instrument comprises a pair of jaw members for grasping tissue, the jaw members may need to be oriented relative to the tissue once properly positioned. Orienting the jaws, however, may prove awkward for a surgeon and may frustrate the positioning of the end effector. In some instances a surgeon may wish to make multiple adjustments to either the position or the orientation of the jaws as the end effector approaches the targeted tissue.
One type of laparoscopic instrument is intended to generate a significant closure force between jaw members to seal small diameter blood vessels, vascular bundles or any two layers of tissue with the application of electrosurgical or RF energy. The two layers may be grasped and clamped together by the jaws, and an appropriate amount of electrosurgical energy may be applied through the jaws. In this way, the two layers of tissue may be fused together. Many electrosurgical forceps also include a knife blade that may be advanced through the jaws to transect the fused tissue. Clamping and cutting features tend to amplify the complexity of a steerable laparoscopic instrument.
To offer a surgeon control of such an instrument a separate actuator may be provided on the handle to initiate each of these features. Since smaller diameter shafts are preferred to capitalize on the benefits of laparoscopic surgery, and since each of the actuators must transmit motion through the elongated shaft, significant ergonomic and design considerations manifested themselves for steerable laparoscopic instruments such as an electrosurgical forceps.